Selective recovery of Sb and Te from the sodium sulfide leach solution of Te-bearing alkaline skimming slag by drop-wise H2O2 addition followed by Na2S–Na2SO3 precipitation

Sb and Te in Te-bearing alkaline skimming slag were extracted into a leach solution using a two-stage sodium sulfide leaching process. In this study, a possible method for selective recovery of Sb and Te from the sodium sulfide leach solution by drop-wise H2O2 addition followed by Na2S–Na2SO3 precipitation was developed. 99% of Sb was precipitated selectively at 50 °C for 100 min with addition of 90 mL H2O2 while Te precipitation was near-zero. Te in the oxidized solution was converted to the form of TeS42− with Na2S, and recovered by Na2SO3 reduction. The results indicated that 95% of Te was precipitated under the optimum conditions: 1.0 of Na2S excess coefficient, 1.75 of Na2SO3 excess coefficient, 50 °C of temperature and 30 min of time. XRD pattern and chemical analysis indicated that the H2O2 oxidation precipitate was NaSb(OH)6 with Sb content of 46.92% and the Na2S–Na2SO3 precipitate was elemental Te with a purity of 98.61%.